This invention relates to automatic vehicle washing installations and, more particularly, to that portion of the installation used to scrub the generally vertical side and end surfaces of the vehicle.
One of the major technical difficulties encountered by the car wash industry has been to achieve a structure which will adequately scrub the side and end surfaces of variously shaped and dimensioned vehicles. In the present state of the art, one vertically disposed brush is used to scrub one side and a portion of each end of the vehicle. A second brush is typically employed to wash the other side and the remaining portions of the vehicle end surfaces. These prior art structures are referred to as "wrap-around" brushes in that they are controlled to pass across the front, down the side and across the rear of the vehicle.
The positioning and movement of wrap-around brushes has in the past required complex sensing and control mechanisms. Frequently the brushes themselves "bounce" or fail to follow irregularities in the vehicle contour, particularly at the transition between end and side surfaces. Because of the difficulties typically encountered in removing road dirt and film from the vehicle surfaces, extensive efforts have been made to increase what is referred to as the "dwell time" of the brushes, that is the amount of time the brushes are in contact with the vehicle surfaces.
One approach to increasing dwell time has been to increase the length of the pivotal arms which support the brushes as they are moved around the vehicle. These efforts have resulted in even more complicated devices having multiply jointed support arms, telescoping support arms or support arms having movable pivot points. Such installations have proven to be extremely expensive, of limited reliability and subject to extensive mechanical wear. Furthermore, the increase in effective length of the support arms has required a corresponding increase in the overall length and width of the installation which, in turn, has resulted in the need for additional building space and land.
A technique for increasing dwell time which is often practiced by car wash operators is simply to slow down the rate at which the vehicle is drawn through the washing installation or the rate at which the installation is moved past the stationary vehicle. Not only does this technique substantially reduce the number of vehicles that can be washed during a given period of time but it also requires the use of additional amounts of water, electricity and chemicals for the adequate cleaning of a single vehicle. These factors directly affect the efficiency and thus the profitability of the car wash installation.
Still another approach to increasing the brush dwell time has been simply to repeat the scrubbing cycle through which the brush passes. This approach also reduces the rate at which vehicles can be washed while increasing the total energy, water and chemical consumption of the installation. Furthermore, unnecessary repeated scrubbing cycles directly reduce the mechanical life of the equipment and significantly contribute to the necessity for maintenance and repair. Examples of the foregoing prior art techniques are shown and described in U.S. Pat. Nos. 3,310,824 (Beer); 3,350,733 (Hanna); 3,428,983 (Seakan); 3,000,025 (Emanuel); 3,522,619 (Weigele); and 3,332,098 (Smith).
It is the principal object of the present invention to provide a method and an apparatus for substantially increasing the effective brush dwell time of a car washing installation without decreasing the rate at which vehicles may be washed, without increasing space requirements of the installaton and without increasing the amount of resources consumed in adequately cleaning the surfaces of a typical vehicle.
A more specific object of this invention is to provide a method and a simple, low maintenance apparatus for double washing the end and side surfaces of a vehicle in a single scrubbing cycle.
Another object of this invention is to provide a brush system which is extremely uncomplicated in design and thus of improved reliability and subject to substantially less mechanical wear.
A further object of this invention is to provide an apparatus for scrubbing the end and side surfaces of a vehicle, which device requires minimal control circuitry and related apparatus.
Still another object is to achieve the foregoing objects in a less expensive and more reliable car wash installation which occupies less space and requires less maintenance and observation.
Many recently designed car wash systems require a particular direction of brush rotation to assist the brush in advancing across the front or rear of the vehicle being washed. Frequently, such rotation of the brushes results in a tendency to lift and bend protrusions such as license plates away from the vehicle surface. Furthermore, because one brush is generally used to scrub at least half of the front and rear surfaces, the rotation of the brush is such that cleaning in recessed areas such as wheel wells invariably lacks uniformity and in many instances is totally inadequate. Heretofore, efforts have been made to resolve this problem by reversing the direction of brush rotation at various times as the brush proceeds about the car. An alternative solution has been simply to repeatedly pass the brush over the surfaces of the vehicle. Periodic brush reversal requires extensive and complex sensing and control equipment and contributes to the mechanical deterioration of the brushing mechanism, particularly gear boxes and the like.
Accordingly, it is another object of this invention to provide an improved method and apparatus for scrubbing the end and side surfaces of vehicles in a manner which substantially preclude the deformation of protrusions such as license plates and which will uniformly clean recessed areas in the vehicle surfaces.
Wrap-around brush systems, as their name implies, are required to make fast and virtually discontinuous transitions in scrubbing direction as they move from the end surfaces of the vehicle to the side surfaces and vice versa. The difficulty in making these transitions while still adequatly scrubbing the vehicle is multiplied when the vehicle design includes irregular protrusions or recessions at or in the vicinity of the vehicle's front and rear corners. Frequently, the brushes lose contact with the vehicle surface as this transition is made; occasionally, the opposite occurs and the brushes "hang up" or become caught in a surface irregularity as the vehicle advances through the installation relative to the brush. This most frequently occurs at the transition between the front and side surfaces.
Thus, it is another object of this invention to provide an improved method and apparatus for scrubbing the end and side surfaces of vehicles while substantially inhibiting the tendency of the brushes to either leave the surface of the vehicle or to become caught in surface irregularities as the vehicle advances.